From c7707e1303b1f7a15f91b236ebba2fd30864f3a4 Mon Sep 17 00:00:00 2001
From: Alec Sammon <alec.sammon@paddle.com>
Date: Sat, 18 May 2024 10:06:36 +0100
Subject: [PATCH]  * use directive

---
 README.md           |  2 +-
 core/directive.go   |  1 +
 core/formencoder.go |  9 ++++++---
 core/header_test.go |  4 ++--
 core/omitempty.go   | 17 +++++++++++++++++
 core/query_test.go  |  4 ++--
 6 files changed, 29 insertions(+), 8 deletions(-)
 create mode 100644 core/omitempty.go

diff --git a/README.md b/README.md
index e27822b..382ef41 100644
--- a/README.md
+++ b/README.md
@@ -56,7 +56,7 @@ type ListUsersInput struct {
 	Page     int     `in:"query=page;default=1"`
 	PerPage  int     `in:"query=per_page;default=20"`
 	IsMember bool    `in:"query=is_member"`
-	Search   *string `in:"query=search,omitempty"`
+	Search   *string `in:"query=search;omitempty"`
 }
 
 func ListUsers(rw http.ResponseWriter, r *http.Request) {
diff --git a/core/directive.go b/core/directive.go
index fa82fc3..9c7e808 100644
--- a/core/directive.go
+++ b/core/directive.go
@@ -17,6 +17,7 @@ func init() {
 	RegisterDirective("default", &DirectiveDefault{})
 	RegisterDirective("nonzero", &DirectiveNonzero{})
 	registerDirective("path", defaultPathDirective)
+	registerDirective("omitempty", &DirectiveOmitEmpty{})
 
 	// decoder is a special executor which does nothing, but is an indicator of
 	// overriding the decoder for a specific field.
diff --git a/core/formencoder.go b/core/formencoder.go
index 76f77be..7757ba0 100644
--- a/core/formencoder.go
+++ b/core/formencoder.go
@@ -2,7 +2,6 @@ package core
 
 import (
 	"github.com/ggicci/httpin/internal"
-	"slices"
 )
 
 type FormEncoder struct {
@@ -10,8 +9,12 @@ type FormEncoder struct {
 }
 
 func (e *FormEncoder) Execute(rtm *DirectiveRuntime) error {
-	if rtm.Value.IsZero() && slices.Contains(rtm.Directive.Argv, "omitempty") {
-		return nil
+	if rtm.Value.IsZero() {
+		for _, d := range rtm.Resolver.Directives {
+			if d.Name == "omitempty" {
+				return nil
+			}
+		}
 	}
 
 	if rtm.IsFieldSet() {
diff --git a/core/header_test.go b/core/header_test.go
index 639db7f..9def1cb 100644
--- a/core/header_test.go
+++ b/core/header_test.go
@@ -29,8 +29,8 @@ func TestDirectiveHeader_Decode(t *testing.T) {
 
 func TestDirectiveHeader_NewRequest(t *testing.T) {
 	type ApiQuery struct {
-		ApiUid   int     `in:"header=x-api-uid,omitempty"`
-		ApiToken *string `in:"header=X-Api-Token,omitempty"`
+		ApiUid   int     `in:"header=x-api-uid;omitempty"`
+		ApiToken *string `in:"header=X-Api-Token;omitempty"`
 	}
 
 	t.Run("with all values", func(t *testing.T) {
diff --git a/core/omitempty.go b/core/omitempty.go
new file mode 100644
index 0000000..f7e002a
--- /dev/null
+++ b/core/omitempty.go
@@ -0,0 +1,17 @@
+// directive: "omitempty"
+// https://ggicci.github.io/httpin/directives/omitempty
+
+package core
+
+// DirectiveOmitEmpty is used with the DirectiveQuery, DirectiveForm, and DirectiveHeader to indicate that the field
+// should be omitted when the value is empty.
+// It does not have any affect when used by itself
+type DirectiveOmitEmpty struct{}
+
+func (*DirectiveOmitEmpty) Decode(_ *DirectiveRuntime) error {
+	return nil
+}
+
+func (*DirectiveOmitEmpty) Encode(_ *DirectiveRuntime) error {
+	return nil
+}
diff --git a/core/query_test.go b/core/query_test.go
index 5691883..f2598b0 100644
--- a/core/query_test.go
+++ b/core/query_test.go
@@ -33,7 +33,7 @@ func TestDirectiveQuery_Decode(t *testing.T) {
 func TestDirectiveQuery_NewRequest(t *testing.T) {
 	type SearchQuery struct {
 		Name    string  `in:"query=name"`
-		Age     int     `in:"query=age,omitempty"`
+		Age     int     `in:"query=age;omitempty"`
 		Enabled bool    `in:"query=enabled"`
 		Price   float64 `in:"query=price"`
 
@@ -41,7 +41,7 @@ func TestDirectiveQuery_NewRequest(t *testing.T) {
 		AgeList  []int    `in:"query=age_list[]"`
 
 		NamePointer *string `in:"query=name_pointer"`
-		AgePointer  *int    `in:"query=age_pointer,omitempty"`
+		AgePointer  *int    `in:"query=age_pointer;omitempty"`
 	}
 
 	t.Run("with all values", func(t *testing.T) {